How To Clean A Top Loading Washing Machine Filter That Smells Like Mildew

A foul, musty odor coming from your top loading washing machine is more than just unpleasant—it’s a sign of hidden buildup. Often, the source lies in the filter or drain pump area, where moisture, lint, soap residue, and organic matter accumulate over time. When this environment stays damp, it becomes a breeding ground for mildew and mold. Left unattended, these microbes not only cause persistent odors but can also compromise cleaning performance and even damage internal components. The good news is that with the right approach, you can eliminate the smell at its source and restore freshness to your laundry routine.

Why Your Washing Machine Filter Develops Mildew Smell

Mildew thrives in dark, moist environments—conditions that are often met inside a washing machine’s filter and drainage system. Unlike front-loaders, top-loading machines don’t always have easily accessible filters, which leads many owners to overlook them entirely. However, most modern top loaders do include a self-cleaning pump filter or trap designed to catch lint, hair, coins, and other debris before they clog the drain hose.

When water sits stagnant after cycles—especially in high-humidity climates or poorly ventilated laundry rooms—microbial growth begins within 24 to 48 hours. Combined with detergent buildup (particularly from gels and pods that leave residues), this creates an ideal habitat for mildew. Over time, the smell spreads from the filter into the drum, affecting clothes and towels even after washing.

“Mildew in washing machines isn't just about odor—it's a hygiene issue. Spores can transfer to fabrics, potentially triggering allergies or skin irritation.” — Dr. Lena Patel, Environmental Health Specialist

Step-by-Step Guide to Cleaning the Filter

Cleaning your washing machine’s filter requires patience and attention to detail. While models vary, the general process remains consistent across most major brands including Whirlpool, Maytag, Samsung, and LG. Follow this comprehensive timeline to ensure thorough results.

1. Unplug the Machine: Safety first. Disconnect the washer from power to prevent accidental startup during maintenance.
2. Check the Owner’s Manual: Locate the filter assembly. In many top loaders, it's found behind a small access panel near the base on the front or side. Some models require removing the outer casing.
3. Prepare for Water Release: Place towels on the floor and position a shallow tray or bucket beneath the access point. Expect up to two cups of standing water to drain out when opening the filter housing.
4. Open the Filter Compartment: Use a screwdriver if needed to remove screws securing the panel. Turn the filter cap counterclockwise to unlock it. Remove slowly to control water flow.
5. Remove and Inspect the Filter: Pull out the mesh or plastic screen. You’ll likely find lint, sand, fabric fragments, and a slimy black or gray film—the telltale sign of mildew.
6. Clean the Filter Thoroughly: Rinse under warm running water. Use an old toothbrush and a solution of equal parts white vinegar and water to scrub away grime. For stubborn biofilm, soak the filter for 15–20 minutes before brushing again.
7. Flush the Housing and Pump Area: With the filter removed, use a flashlight to inspect the interior chamber. Wipe down walls with a vinegar-soaked cloth. Pour ½ cup of distilled white vinegar into the cavity to kill residual spores.
8. Reinstall the Filter: Ensure the seal is intact and free of debris. Screw the filter back in tightly by hand—do not overtighten.
9. Run a Cleaning Cycle: Restore power and run a hot water cycle (without clothes) using one cup of white vinegar or a dedicated washing machine cleaner. This flushes the entire system, including hoses and drum.

Tip: Perform this cleaning every 3–4 months to prevent odor recurrence, especially if you wash frequently or use cold water cycles.

Do’s and Don’ts When Cleaning a Mildew-Smelling Filter

Do’s	Don’ts
Use white vinegar and baking soda—they’re natural disinfectants and deodorizers.	Use bleach directly on the filter unless specified by the manufacturer; it can degrade rubber seals.
Wear gloves to protect hands from bacteria and sharp debris.	Ignore signs of slow drainage—this often precedes severe clogs.
Inspect the filter housing for cracks or insect nests.	Force open a stuck filter; apply penetrating oil and wait 10 minutes instead.
Leave the filter out and door open for several hours post-cleaning to air-dry the interior.	Forget to check the lint trap in your dryer—cross-contamination can reintroduce fibers.

Real Example: How One Homeowner Fixed Persistent Odors

Sarah M., a mother of three in Tampa, Florida, noticed her towels smelled sour despite using extra detergent. She tried running empty hot cycles with bleach, but the problem returned within days. After researching online, she discovered her Whirlpool Cabrio had a hidden filter near the front kickplate. Upon opening it, she pulled out a dense wad of pet hair and a thick layer of black slime. She cleaned the filter with vinegar, wiped the housing, and ran a cleaning cycle. Not only did the odor vanish, but she also noticed improved spin efficiency and faster draining. “I had no idea this part existed,” she said. “Now I clean it every season—and my laundry has never smelled fresher.”

Additional Maintenance Tips to Prevent Future Mildew Buildup

Prevention is far easier than remediation. Incorporating simple habits into your laundry routine significantly reduces the risk of microbial growth.

• Leave the Lid Open Between Cycles: Allow airflow to dry the drum and gasket areas. Even top loaders with agitators benefit from ventilation.
• Use High-Efficiency (HE) Detergent: Regular detergents produce excess suds that trap moisture and accelerate residue buildup.
• Avoid Overloading: Crowded loads reduce rinse effectiveness, leaving soap and moisture behind.
• Clean the Dispenser Drawer Monthly: Remove and soak it in warm vinegar water to dissolve detergent cake.
• Wipe Down the Drum Rim: Use a microfiber cloth weekly to remove any visible moisture or film around the upper tub edges.

Tip: Add ½ cup of citric acid to a monthly hot water cycle to dissolve mineral deposits and inhibit microbial adhesion.

Frequently Asked Questions

How do I know if my top loader has a filter?

Not all top loaders have user-accessible filters, but most models manufactured after 2005 do. Check your owner’s manual or look for a small access panel on the front lower portion of the machine. Machines with \"self-cleaning pump\" features typically include a serviceable filter trap that still requires periodic inspection.

Can I use bleach instead of vinegar?

Bleach can be effective for sanitizing the drum but should be used cautiously. It may corrode rubber seals in the filter housing and doesn’t break down organic sludge as effectively as acidic cleaners like vinegar. If using bleach, follow manufacturer guidelines and avoid mixing it with vinegar—this creates toxic chlorine gas.

What if the smell persists after cleaning the filter?

Residual odor may linger in hoses or the outer tub. Run two consecutive cleaning cycles: one with vinegar, followed by another with a commercial washing machine cleaner like Affresh or Tide Washer Cleanser. Also, inspect the drain hose for kinks or standing water, and ensure the standpipe is properly vented.

Expert-Recommended Cleaning Checklist

To maintain optimal hygiene and performance, follow this actionable checklist every 3–4 months—or immediately if you detect musty smells.

1. ✅ Unplug the washing machine
2. ✅ Locate and open the filter access panel
3. ✅ Drain residual water into a tray
4. ✅ Remove filter and rinse thoroughly
5. ✅ Scrub filter with vinegar and soft brush
6. ✅ Clean interior housing with vinegar cloth
7. ✅ Inspect for debris, insects, or damage
8. ✅ Reinstall filter securely
9. ✅ Run a hot water cleaning cycle with 1 cup white vinegar
10. ✅ Leave lid open for 4–6 hours to dry interior

“The key to a long-lasting washing machine isn’t heavy-duty cycles—it’s consistent light maintenance. A five-minute filter check every few months saves hours of repair later.” — Mark Tran, Appliance Technician with 18 years of field experience

Conclusion: Take Control of Your Laundry Hygiene Today

A smelly washing machine filter isn’t just an inconvenience—it’s a signal that unseen contaminants are compromising your home’s cleanliness. By identifying, cleaning, and maintaining the filter in your top loading washer, you eliminate the root cause of mildew odors and extend the life of your appliance. The process takes less than 30 minutes and requires only basic tools and household supplies. More importantly, it restores confidence in your laundry results: clothes come out truly clean, not just wet and scented.

Don’t wait for the stench to worsen or performance to decline. Schedule your next filter inspection now—mark it on your calendar, set a reminder, or tie it to a seasonal change. Small actions yield big returns in appliance longevity and household wellness. Share your experience, ask questions, or pass this guide along to someone battling mysterious laundry smells. Freshness starts with awareness—and action.

💬 Have you cleaned your washer’s filter recently? Share your story or tip in the comments below—your insight could help others reclaim fresh, odor-free laundry days!